A key may have different meanings depending on culture and time period, but some of the most popular meanings include privileged access, answer to a puzzle and authority. The key has been widely used as a symbol for many centuries among many cultures.
In almost all cultures, the key symbolizes special privilege to access an exclusive area like the kingdom of heaven. Some cultures believe the key symbolizes authority to exercise certain powers over a given community. It is also worth noting that people believe having the key indicates being knowledgeable in issues that most people do not know about.